Apparatus for extruding



April 19, 1966 c. E. TAYLOR ETAL 3,246,366

APPARATUS FOR EXTRUDING Original Filed Dec. 21, 1961 ll w 52 H N 2' LI.

INVENTORS ROBERT G. HALL BY CHALLEN E.TAYLOR g imrmev United StatesPatent 3,246,366 APPARATUS FOR EXTRUDENG Challen E. Taylor, Waulregan,and Robert George Hail, Lihertyvilie, liL, assignors to The GoodyearTire dz Rubber Company, Akron, Shin, a corporation of Ohio Originalapplication Dec. 21, 1961, Ser. No. 160,981, new Patent No. 3,183,238,dated May 11, 1965. Divided and this application Nov. 17, 1%4, Ser. No.416,1'7

3 Claims. (Cl. 13-14) This is a division of application Serial No.160,981, filed December 21, 1961, now Patent No. 3,183,288, dated May1], 1965.

This invention relates to an apparatus used in conjunction withextruders and more particularly to an apparatus for lubricating theinterior surface of an extrusion as it leaves the extruder.

In the process of extruding from rubber or plastic continuous lengths oftubular or closed cross section such as hose, inner tubes, sealinggaskets, etc., it is usually necessary to insert a lubricant of sometype into the interior of the extrusion tocoat the surface so as toprevent sticking together when collapsed. Soapstone, mica dust, zincstearate and other dry dust lubricants have been used extensively forthis purpose as well as various liquid lubricants on occasion, but it isapparent that the dust and contamination from such lubricants creates avery substantial problem both in the cleanliness and appearance of theextrusion and complications in the additional processing required onsome extrusions. In many instances it is necessary to provide additionalmeans to gather the excess dust or liquid lubricants as it is notpossible to use the minimum amount and be assured of thoroughlubrication.

It has been found that a liquid lubricant such as soap which has beenaerated to produce a foam of the lubricant, provides not only anexcellent lubricant but also eliminates substantially all contaminationand cleanliness problems. The foam also provides a very uniformlubricating film over the entire surface since it clings well and ondisintegration, leaves no surplus of lubricating material. Thiseliminates the need for additional equipment to collect the excess orloose material and as a result reduces waste and eliminates the usualuntidiness of the surrounding work area. The apparatus to aerate thelubricant is simple in construction and may be attached to the extruderin place of the present apparatus used for the other type of lubricantswithout any substantial modification. It is, therefore, an object ofthis invention to provide a new and novel apparatus to provide thelubricant for the interior of a hollow extrusion as it is extruded.

Another object of the invention is to provide an apparatus for suchlubrication that eliminates much of the usual contamination and dustencountered.

A further object of the invention is to provide a simple and inexpensiveapparatus to create the lubricant.

A still further object of the invention is an apparatus for providing amore uniform and positive lubrication of the interior of an extrusion.

Another object of the invention is to provide an apparatus that makes itpossible to use a minimum of lubricant for a thorough lubrication andeliminate the necessity of collecting or disposing of the excess.

These and other objects and advantages of this invention will becomeapparent hereinafter as the description thereof proceeds, the novelfeatures, arrangements and combinations being clearly pointed out in thespecification'as well as the claims thereunto appended.

In the drawings:

FIG. 1 is a schematic and partial sectional plan view illustrating theinvention;

FIG. 2 is a detailed sectional view showing a portion of the invention;

FlG. 3 is an end view of a portion of the apparatus; and

FIG. 4 is a modification of a portion of the apparatus.

For the purposes of illustration, in FIG. 1 a typical screw extruder 1is illustrated in which the extruder screw 2 lies in barrel 3. Therubber or plastic material is fed in the form of a ribbon 4 into barrel3 and is forced by the screw 2 through the openings 5 in the spider 6 atthe end of the barrel 3. Projecting outwardly and centrally from spider6 is a mandrel 7 which along with the extruder die 8 forms the extrudedtube 9 as the material is extruded from the machine. As shown, thespider 6 and portion thereof containing openings 5 is an integralstructure but as in many extruders, the spider and breaker plate(portion having openings) are separate parts assembled in the desiredrelation. The mandrel and die set-up is of conventional constructionused in conjunction with extruders for the manufacture of tubing orother extruded hollow extrusions and the set-up illustrated is onlyshown as an example.

In order to lubricate the interior surface of the tube 9 a foam 10 of anaerated liquid material is continuously passed into the interior of theextruded tube 9 as it leaves the extrusion die 8. The foam 10 enters theinterior of tube 9 by means of passageway 11 in mandrel 7 generallyextending axially from the outlet end into the spider 6 to connect withpassageway 12 therein which extends out of the spider radially betweenthe openings 5 to the exterior periphery thereof. The openings 5 inspider 6, as best seen in FIG. 3, provide the means for the rubber inthe extruder barrel 3 to pass into the extruder die and mandrelassembly. In many presently used extruders, the passageway 12 isincluded in spider 6 for use in inserting the usual lubricants into theinterior of an extruded tube.

In order to provide the aerated lubricant, an apparatus such as seen inFIG. 1 may be used. A reservoir 13 holding a supply of liquidlubricating material such as soap is mounted adjacent the extruder. Afoam generator 14 is connected to the reservoir 13 by means of tubing 15which as shown includes a filter 16 to remove any foreign particles inthe liquid lubricant as it passes from the reservoir 13 to the generator14. A valve 17 preferably is also included in the tubing 15 to moreaccurately control the amount of liquid lubricant flowing between thereservoir 13 and the generator 14. It has been found that by heating theliquid lubricant in reservoir 13 in any desired manner that the foamgeneration is improved but in many instances this is not necessary.

The generator 14, as shown, is a closed container with a connecting tube18 joining the top of the container to the end of passageway 12 inspider 6. Adjacent the bottom of the generator 14 is a foam generatorscreen 19. In the form shown in FIG. 2 the foam generating screen 19 ismade up of rings 26 and 21 of resilient material such as rubber aroundthe opposite sides of the periphery of a foraminous element 22. Asshown, foraminous element 22 covers substantially the cross sectionalarea of generator 14 and is spaced from the bottom thereof so that airpressure as will be explained later, can enter the liquid material overthe entire area of the generator. Foraminous element 22 is of a materialsuch as heavy twill cloth although fine screen or other types offoraminous material may be used. The screen 19 is clamped snugly in thefoam generator 14 and tubing 15 is connected to the side of the foamgenerator 14 so that the liquid material enters the foam generator 14immediately above the foam generating screen 19. It has been found thatsatisfactory foam generation occurs when the liquid soap level in thegenerator is approximately one-third of the volume of generator 14.

In order to assure uniform flow of the lubricant to the generator, airpressure is applied in the reservoir to the surface of the liquidthrough pressure line 23 from a source of compressed air (not shown) tomaintain the liquid lubricant 24 under a predetermined constantpressure. Regulator 25 is used to control the amount of pressure on theliquid lubricant 24 in reservoir 13.

To generate or convert the liquid lubricant into foam, air pressure isintroduced in the bottom of generator 14 below generating screen 19 andpasses through foraminous element 22 into the liquid lubricant above thefoam generating screen 19. As the air under pressure passes into theliquid lubricant through the f-oraminous element 22, it is dividedthereby into many small streams thus converting the liquid into a foammade up of a multitude of fine bubbles. Regulator 26 controls the amountof air pressure introduced into the foam generator 14.

As shown, the same pressurized line 23 furnishes the compressed air toboth the reservoir 13 and the foam generator 14. It has been found thata pressure of approximately 8 p.s.i. on the liquid lubricant in thereservoir and 4 psi. into the foam generator produces a continuous foamflowing at the proper rate into the extruded tube 9. It is apparent thatseparate air pressure lines or pressurized gaseous materials other thanair may be used to accomplish the desired results. As shown, shut-offvalves 27 and 28 may be included in lines 23 and 18 respectively to shutoff the flow through the lines when desired such as machine shut down orduring a die changeover.

Another form of foam generating screen 29 is illustrated in FIG. 4. Aforaminous element 30 extends across opening 31 centrally positioned ina pad 32 which would lie on the bottom of generator 14. The edges offoraminous element 30 are embedded in pad 32 and are spaced from thebottom surface 33 thereof.

As the foam is generated in generator 14 it passes out of the generatorinto tubing 18, thence to the spider 6 and through the passageway 12 inthe spider and passage way 11 in the mandrel into the interior of theextruded tube 9. The interior of the tube 9 is completely filled withthe foam and in a short period of time the foam deteriorates to leavethe film of lubricant upon the interior surface of tube 9. By the properregulation of the pressure on the reservoir 13 and generator 14 and therate of flow of the foam 10 into the extruded tube 9, the extent offoaming may be accurately controlled so as to provide only an amount offoam necessary to properly lubricate the interior of the tube 9 andeliminate a surplus of liquid that does not adhere to the tube surface.By providing the lubricant in the form of a foam the interior surface iscompletely lubricatedwith a minimum amount of material due to theadherence to the surface by the film formed as the foam deteriorates.

While certain representative embodiments and details have been shown forthe purpose of illustrating the invention, it will be apparent to thoseskilled in the art that various changes and modifications may be madetherein without departing from the spirit or scope of the invention.

Having thus fully described our invention, what we claim and desire tosecure by Letters Patent of the United States is:

1. In an extruder apparatus wherein the hollow extrusion passes from theextrusion die in a continuous length, the combination with saidapparatus of a device to lubricate continuously the interior surface ofsaid extrusion, said device comprising a closed container in whichliquid lubricating material is aerated, a foraminous element adjacentthe bottom of said container, means to feed the liquid lubricatingmaterial into said container above said foraminous element, means tocontinuously pass a pressurized gas through said foraminous element intosaid lubricating material to continuously aerate said lubricatingmaterial to form a foam there-of, and means connecting said containerthrough the interior of said extrusion die to the interior of theextrusion whereby the foam passes continuously from. the container intothe extrusion.

2'. Apparatus as claimed in claim 1 which includes means to correlatethe feed and aeration of the lubricating material with the speed of theextrusion from the die.

3. In an extruder apparatus wherein a hollow extrusion passes from theextrusion die in a continuous length, the combination with saidapparatus of a device to lubricate continuously the interior surface ofsaid extrusion, said device comprising a reservoir of liquid lubricatingmaterial, a closed container in which said lubricating material isaerated to form a foam, means connecting said reservoir and closedcontainer through which the lubricating material passes from thereservoir to said container, means to apply pressure to said lubricatingmaterial in said reservoir to cause the lubricating material tocontinuously flow at a uniform rate from said reservoir to saidcontaincr, a foraminous element in said closed container adjacen-t thebottom thereof, means to continuously pass a pressurized gas throughsaid foraminous element into said lubricating material to continuouslyaerate the lubricating material, thus forming a foam of a multitude ofminute bubbles, means connecting said closed containerand the extrusiondie through which the foamed lubricating material flows into theinterior of the extrusion and means to coordinate the rate of flow ofthe foamed lubricating material with that of the extrusion.

References Cited by the Examiner UNITED STATES PATENTS 1,192,645 7/1916Koerting 239590 1,995,215 3/1935 Mehlsen et al 239343 2,119,906 6/1938Dorman 239 343 2,519,375 8/1950 J-argstorlf et al 1814 2,632,205 3/1953Fitz Harris 1814 X 2,690,592 10/1954 Schanz 18-l4 3,103,409 9/1963Bohres et al 18l4 X 3,135,630 6/1964 Bielinski et a1. 239--343 X J.SPENCER OVERHOLSER, Primary Examiner.

WILLIAM J. STEPHENSON, Examiner.

1. IN AN EXTRUDER APPARATUS WHEREIN THE HOLLOW EXTRUSION PASSES FROM THEEXTRUSION DIE IN A CONTINUOUS LENGTH, THE COMBINATION WITH SAIDAPPARATUS OF A DEVICE TO LUBRICATE CONTINUOUSLY THE INTERIOR SURFACE OFSAID EXTRUSION, SAID DEVICE COMPRISING A CLOSED CONTAINER IN WHICHLIQUID LUBRICATING MATERIAL IS AERATED, A FORAMINOUS ELEMENT ADJACENTTHE BOTTOM OF SAID CONTAINER, MEANS TO FEED THE LIQUID LUBRICATINGMATERIAL INTO SAID CONTAINER ABOVE SAID FORAMINOUS ELEMENT, MEANS TOCONTINUOUSLY PASS A PRESSURIZED GAS THROUGH SAID FORAMINOUS ELEMENT INTOSAID LUBRICATING MATERIAL TO CONTINUOUSLYAERATE SAID LUBRICATINGMATERIAL TO FORM A FOAM THEREOF, AND MEANS CONNECTING SAID CONTAINERTHROUGH THE INTERIOR OF SAID EXTRUSION DIE TO THE INTERIOR OF THEEXTRUSION WHEREBY THE FOAM PASSES CONTINUOUSLY FROM THE CONTAINER INTOTHE EXTRUSION.